Missing students and Mexico's worst massacre

Mexico City, Mexico - Every year in Mexico they march to remember the students killed in the country's worst massacre.

On October 2, 1968 - 10 days before the Olympics - police and soldiers opened fire on unarmed students, killing dozens. The final death toll is still unknown to this day. The Tlatelolco massacrein Mexico City was the most dramatic incident in the battle by successive administrations of the PRI, or Institutional Revolutionary Party, to suppress political opposition.

But this year's remembrance was different. Demonstrations in Mexican cities were given added poignancy by the death and disappearance of students in southern Guerrero state less than a week ago.

There have been a series of inconclusive investigations into what happened 46 years ago; the investigation into what happened to the six dead and 43 missing in Iguala city is just beginning. In Guerrero state, in the town of Chilpancingo, some of the families and friends of those missing joined thousands on the streets on Thursday to call for the safe return of the students.

We know that the local police took them away. They know where our children are. They know where they left them. We want them back. We want them back in the same condition that they were taken.

- Margarito Ramirez, father of missing son

The trainee teachers from Ayotzinapa's Normal School, also known as "normalistas" , had been protesting increased university fees and government education reforms.

They were last seen last Friday being forced into police vehicles. Six students were also killed when police opened fire on buses the students - with a reputation for radical activism - had hijacked.

Twenty-two police were arrested after the incident. Many in Guerrero say they handed over the 43 students to criminal gangs - a line of investigation confirmed by the state Attorney General Iñaki Blanco.

Some 80,000 people have been killed in drug-related violence in Mexico since 2006, and another 22,000 people remain unaccounted for.

Margarito Ramirez who has been looking for his son, Carlos, told Al Jazeera: "We know that the local police took them away. They know where our children are. They know where they left them. We want them back. We want them back in the same condition that they were taken."

In the aftermath of the latest tragedy in a state that has one of the worst reputations for drug-related violence in Mexico, some of those marching in Chilpancingo said it was further evidence that the country's entire system was in collapse, and that politicians were either unwilling or unable to act.

Perseo Quiroz of Amnesty International told Al Jazeera he is already worried by the efforts in Guerrero to determine what happened. "We have concerns over the way the investigation is being conducted. There needs to be a proper process. All the authorities that may have been involved and that may have information should be asked to provide it."

He added: "Why did the police intervene [in the protests] last week? I don't see the local government asking these questions. Also, the first few hours are crucial for the disappeared and now we have had days. As more time passes it becomes much harder to find them."

Quiroz is one of many to draw comparisons to what happened almost half a century ago. "Students have always been a massive group in demonstrations. And now, just as in 1968, we ask the Mexican governments to ensure that proper protocols are observed in the use of force."

The recent events were on the minds of those students marching in Mexico City. Some had painted the number 43 - the number of those missing - onto placards and banners. The Guerrero students had been due to travel to Mexico City to take part in the annual October 2 demonstrations.

Demonstrators yell slogans during a march commemorating the anniversary of the Tlatelolco massacre in Mexico City [AP]

Many of those who spoke to Al Jazeera at the march alleged high-level complicity.

"People are still being disappeared, and students are still being killed," Raul Garcia said. "The government keeps responding with repression."

Maria Garcia told Al Jazeera, "When they don't like what we say or do in Mexico, this is what happens."

Dozens of Guerrero state police and Mexican military are continuing to search for the students, alongside the families and friends of the missing who have been frustrated. They have little information to go on, and are hunting for clues in a difficult and hostile terrain.

One of the country's poorest states, Guerrero also had the highest murder rate in 2013, fuelled by a turf war between splinter groups of drug cartels. The state's governor has offered $80,000 to anyone who comes forward with information about the missing students.

In the 46 years since the October 2massacre, there is still no consensus on how many were killed in that Mexico City square, or who gave the order to carry it out. Those hunting for the missing students are hoping for more conclusive information about the fate of the missing this time around.